The present invention relates to a cell-forming assembly which is equipped in a household aquarium so as to divide a part of its inner space into cells such that the tropical fishes such as "guppy", "platy", "swordtail" and "betta" are separated from other usual aquarium fishes accommodated in the same household aquarium, wherein the upbringing of eggs or fry (i.e., young of fishes) spawned by adult fishes in those cells is ensured.
Popular household aquariums which have been widely used comprise in general a transparent surrounding wall of glass or plastics and are of a box-like shape.
Such a household aquarium may be used to accommodate not only the same species of aquarium fishes but also in some cases different species thereof. Though there may be no problem in the former case, it has been observed that in the latter cases the different aquarium fishes often fight with one another to mutually hurt or occasionally devour one another. In particular, inoffensive aquarium fishes can hardly share the same aquarium space with the other fishes such as guppy, platy, swordtail and betta.
To resolve such a problem, it would be feasible to simply form a fixed untransparent cell or cells within a household aquarium so that various kinds of fishes can be accommodated in the same aquarium for watchers' enjoyment. Such an aquarium would not excite amusement because, in particular, the outstretched fins of the fighting fishes such as betta cannot be observed when they often frighten other fishes away to quarrel over their territories. They would not so behave, if they were separated by the simple cell from the other fishes within the same aquarium.
Besides, the viviparous fishes such as guppy, platy and swordtail are likely to eat their eggs or fry. It is therefore difficult to propagate the eggs or fry in one and the same aquarium.